Chris R. Lunsford

Sperm whale population structure in the eastern and central North Pacific inferred by the use of single-nucleotide polymorphisms, microsatellites and mitochondrial DNA.

We use mitochondrial DNA (mtDNA) (400 bp), six microsatellites and 36 single‐nucleotide polymorphisms (SNPs), 20 of which were linked, to investigate population structure of sperm whales (Physeter macrocephalus) in the eastern and central North Pacific. SNP markers, reproducible across technologies and laboratories, are ideal for long‐term studies of globally distributed species such as sperm whales, a species of conservation concern because of both historical and contemporary impacts. We estimate genetic differentiation among three strata in the temperate to tropical waters where females are found: California Current, Hawai`i and the eastern tropical Pacific. We then consider how males on sub‐Arctic foraging grounds assign to these strata. The California Current stratum was differentiated from both the other strata (P < 0.05) for mtDNA, microsatellites and SNPs, suggesting that the region supports a demographically independent population and providing the first indication that males may exhibit reproductive philopatry. Comparisons between the Hawai`i stratum and the eastern tropical Pacific stratum are not conclusive at this time. Comparisons with Alaska males were statistically significant, or nearly so, from all three strata and individuals showed mixed assignment to, and few exclusions from, the three potential source strata, suggesting widespread origin of males on sub‐Arctic feeding grounds. We show that SNPs have sufficient power to detect population structure even when genetic differentiation is low. There is a need for better analytical methods for SNPs, especially when linked SNPs are used, but SNPs appear to be a valuable marker for long‐term studies of globally dispersed and highly mobile species.

Using Models of Social Transmission to Examine the Spread of Longline Depredation Behavior among Sperm Whales in the Gulf of Alaska

Fishing, farming and ranching provide opportunities for predators to prey on resources concentrated by humans, a behavior termed depredation. In the Gulf of Alaska, observations of sperm whales depredating on fish caught on demersal longline gear dates back to the 1970s, with reported incidents increasing in the mid-1990s. Sperm whale depredation provides an opportunity to study the spread of a novel foraging behavior within a population. Data were collected during National Marine Fisheries Service longline surveys using demersal longline gear in waters off Alaska from 1998 to 2010. We evaluated whether observations of depredation fit predictions of social transmission by fitting the temporal and spatial spread of new observations of depredation to the Wave of Advance model. We found a significant, positive relationship between time and the distance of new observations from the diffusion center (r2 = 0.55, p-value  = 0.003). The data provide circumstantial evidence for social transmission of depredation. We discuss how changes in human activities in the region (fishing methods and regulations) have created a situation in which there is spatial-temporal overlap with foraging sperm whales, likely influencing when and how the behavior spread among the population.

National Marine Fisheries Service longline survey data report and survey history, 1990-2014

This report discusses the history and methods of the National Marine Fisheries Service’s (NMFS) longline surveys of the Gulf of Alaska, eastern Bering Sea, and eastern Aleutian Islands and summarizes the 1990-2014 survey results. The primary purpose of the NMFS longline survey is to determine the relative abundance and length composition of sablefish, Anoplopoma fimbria; shortspine thornyhead, Sebastolobus alascanus; rougheye rockfish, Sebastes aleutianus; blackspotted rockfish, Sebastes melanostictus; and shortraker rockfish, Sebastes borealis, in the Gulf of Alaska, eastern Bering Sea, and Aleutian Islands region. Only the abovementioned species and arrowtooth flounder, Atheresthes stomias, are discussed in this report. Catch results are listed for Pacific cod, Gadus macrocephalus; Pacific halibut, Hippoglossus stenolepis; giant grenadier, Albatrossia pectoralis; Greenland turbot, Reinhardtius hippoglossoides; spiny dogfish, Squalus acanthias; and Pacific sleeper shark, Somniosus pacificus. The survey area covers the upper continental slope and selected gullies of the Gulf of Alaska and the upper continental slope of the eastern Bering Sea and Aleutian Islands region. Overall sablefish abundance indices (relative population number (RPN) and relative population weight (RPW)) for the Gulf of Alaska decreased from 1990 to 2014. Shortspine thornyhead RPN for the Gulf of Alaska increased from 1990 to 2014 and RPW increased from 1990 to 2014. Rougheye and blackspotted rockfish RPN for the Gulf of Alaska increased from 1992 to 2014 and RPW increased from 1992 to 2014. Gulf of Alaska RPN for shortraker rockfish increased from 1992 to 2011 followed by a decrease during 2012-2014. While shortraker rockfish RPWs fluctuated over the years there was an overall increase in RPWs from 1992 to 2014. Arrowtooth flounder RPN for

Evidence of multiple paternity in quillback rockfish (Sebastes maliger)

Multiple paternity, also termed polyandry, is a reproductive strategy that can increase the genetic variation within a brood to help preserve diversity within a population. A paternity analysis using multilocus microsatellites revealed that 8 of 25 (32%) quillback rockfish (Sebastes maliger) females mated with more than one male. Of the eight broods sired by multiple males, three were sired by two males and five were sired by three males. Polyandry is likely an important consideration when managing rockfish stocks for genetic diversity and productivity. The probability of polyandry increased with increasing weight and condition factor of the female, but not with increasing age or length. These results suggest polyandry is a common mating strategy in quillback rockfish in Alaska and may be related to female size.

Exploiting the sound-speed minimum to extend tracking ranges of vertical arrays in deep water environments

Underwater acoustic vertical arrays can localize sounds by measuring the vertical elevation angles of various multipath arrivals generated by reflections from the ocean surface and bottom. This information, along with measurements of the relative arrival times of the multipath, can be sufficient for obtaining the range and depth of an acoustic source. At ranges beyond a few kilometers ray refraction effects add additional multipath possibilities; in particular, the existence of a sound-speed minimum in deeper waters permits purely refracted ray arrivals to be detected and distinguished on an array, greatly extending the tracking range for short-aperture systems. Here, two experimental vertical array deployments are presented. The first is a simple two-element system, deployed using longline fishing gear off Sitka, AK. By tracking a tagged sperm whale, this system demonstrated an ability to localize this species out to 35 km range, and provide estimates of the detection range of these animals as a function...

Southeast Alaska Sperm Whale Avoidance Project: Collaboration among fishermen, acousticians, biologists and managers to reduce longline depredation in the Gulf of Alaska.

In the eastern Gulf of Alaska, depredation of demersal longline fishing gear set for sablefish (Anoplopoma fimbria) by sperm whales (Physeter macrocephalus) has occurred since at least the mid‐1970s. In 1995, with the implementation of Individual Fishing Quotas, the season expanded from a 2 week derby style fishery to 8 months. This change allowed more opportunity for whales to depredate longline gear and reports of depredation increased resulting in economic loss to the fleet. Beginning in 2003, the North Pacific Research Board funded a collaborative study among fishermen, scientists, and managers to collect quantitative data on longline depredation. The goal of the Southeast Sperm Whale Avoidance Project (SEASWAP) is to determine the mechanics of the depredation, characterize the whales involved, and to recommend changes in fishing behavior to reduce depredation. The longline fleet provided fishing data and allowed researchers to collect behavioral, genetic, and acoustic data in conjunction with their f...

Depth, orientation, and acoustics of sperm whales (Physeter macrocephalus) under natural and depredation foraging conditions in the Gulf of Alaska

In July 2007 bioacoustic tags were attached to adult sperm whales in the Gulf of Alaska under both natural foraging conditions, and situations wherein the animals were depredating sablefish from commercial longlining vessels. A small Rigid‐Hull Inflatable was used to approach and attach a suction‐cup acoustic recording tag on 13 occasions and stayed on animals for a total of 168 hours, yielding 80 h of depth, orientation, and acoustic data. These results, combined with passive acoustic tracking and underwater video‐camera data, indicate that sperm whales depredate at depths shallower than 50 m, compared to natural foraging depths of 300‐400 m in the area. During depredation the animals demonstrate changes in pitch and roll that are greater when compared with normal foraging behavior. Observations on the acoustic behavior of the animals are noted as well. The fact that these normally deep‐diving animals depredate so close to the surface has interesting implications for both depredation‐reduction strategies...